A typical data storage system includes a rigid housing having a base and top cover that encloses a variety of components. The components include one or more discs having data surfaces for storage of digital information. The disc(s) are mounted on a rotor of a spindle motor. The spindle motor causes the disc(s) to spin and the data surfaces of the disc(s) to pass under respective aerodynamic bearing disc head sliders. The sliders carry transducers, which write information to and read information from the data surfaces of the discs.
Recently, there has been a rapid increase in the production of smaller and lighter weight disc drives in the disc drive industry. These smaller sized disc drives are typically used in handheld or portable devices, such as cell phones and digital music players. When producing smaller sized disc drives for portable devices, it is often desirable to include a spindle motor with a high electromagnetic (EM) performance level. Spindle motors having high EM performance levels include low power consumption, a high torque constant (Kt) and a high voltage margin at low temperatures (to overcome start up problems). It is also desirable to include spindle motors that have small z-heights. Small z-heights allow the disc drive to be as small as possible for use in portable devices. However, in general, the smaller the z-height of a spindle the motor the lower the EM performance level.
In conventional small sized disc drives, the printed circuit board assembly (PCBA) is attached to the base of the disc drive and includes an aperture. The aperture in the PCBA accommodates a housing of the spindle motor such that the z-height of the spindle motor can be as large as possible relative to the thickness of the disc drive. However, a diameter of the aperture in the PCBA can be rather large and, therefore, compromises space needed for holding printed circuit board components. Although a small aperture in the PCBA for a smaller sized spindle motor allows more room for printed circuit board components, a small aperture in the PCBA for a smaller sized spindle motor compromises EM performance levels.
Embodiments of the present invention provide solutions to these and other problems, and offer other advantages over the prior art.